[PATCH 4.16 180/279] drm/exynos/mixer: fix synchronization check in interlaced mode

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrzej Hajda <a.hajda@xxxxxxxxxxx>

[ Upstream commit 2eced8e917b060587fc8ed46df41c364957a5050 ]

In case of interlace mode video processor registers and mixer config
register must be check to ensure internal state is in sync with shadow
registers.
This patch fixes page-faults in interlaced mode.

Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Signed-off-by: Inki Dae <inki.dae@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/exynos/exynos_mixer.c |   10 ++++++++++
 drivers/gpu/drm/exynos/regs-mixer.h   |    1 +
 2 files changed, 11 insertions(+)

--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -494,6 +494,7 @@ static void vp_video_buffer(struct mixer
 
 	spin_lock_irqsave(&ctx->reg_slock, flags);
 
+	vp_reg_write(ctx, VP_SHADOW_UPDATE, 1);
 	/* interlace or progressive scan mode */
 	val = (test_bit(MXR_BIT_INTERLACE, &ctx->flags) ? ~0 : 0);
 	vp_reg_writemask(ctx, VP_MODE, val, VP_MODE_LINE_SKIP);
@@ -711,6 +712,15 @@ static irqreturn_t mixer_irq_handler(int
 
 		/* interlace scan need to check shadow register */
 		if (test_bit(MXR_BIT_INTERLACE, &ctx->flags)) {
+			if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags) &&
+			    vp_reg_read(ctx, VP_SHADOW_UPDATE))
+				goto out;
+
+			base = mixer_reg_read(ctx, MXR_CFG);
+			shadow = mixer_reg_read(ctx, MXR_CFG_S);
+			if (base != shadow)
+				goto out;
+
 			base = mixer_reg_read(ctx, MXR_GRAPHIC_BASE(0));
 			shadow = mixer_reg_read(ctx, MXR_GRAPHIC_BASE_S(0));
 			if (base != shadow)
--- a/drivers/gpu/drm/exynos/regs-mixer.h
+++ b/drivers/gpu/drm/exynos/regs-mixer.h
@@ -47,6 +47,7 @@
 #define MXR_MO				0x0304
 #define MXR_RESOLUTION			0x0310
 
+#define MXR_CFG_S			0x2004
 #define MXR_GRAPHIC0_BASE_S		0x2024
 #define MXR_GRAPHIC1_BASE_S		0x2044